Devices and methods for sampling surfaces and materials include self-contained, single service swabs for removing a sample from a surface and detecting adenosine triphosphate (ATP) in the sample by measuring the reaction of sample ATP with luciferin-luciferase to generate luminescence (light). The light from the reaction can be detected using an analyzer such as a luminometer, photodiode or photomultiplier. It is desirable to provide similar such devices and methods that are adapted to provide a stable test unit, for example one that will not leak and/or engage prematurely. Such a test unit can allow for culturing and/or detecting possibly hazardous microbes; maintaining the integrity of samples in non-laboratory conditions; transporting test samples such as DNA samples for later testing, for example in forensics; and maintaining samples in extreme conditions such as occur during space travel. It is also beneficial to provide a means to eliminate or reduce the risk that hazardous substances, for example cultured pathogens, will be released into the environment from the test unit.